The primary aim of the proposed study is to improve on radiological diagnostic information, while reducing patient dose and cost. This is to be accomplished by an evaluation and study program first of x-ray intensifiers, and thereafter of video components used in radiological systems. Its goals are to establish criteria for specification of device performance in a manner that will allow for an absolute comparison between components of the same kind from different vendors. During the first year a vibration proof optical bench was constructed. It carries a computer controlled photometer to determine the intensity distribution of the light output from an x-ray image intensifier (XII). The x-ray irradiation of the XII is either distributed uniformly of through bar patterns or pinholes, with x-rays of known intensity and energy. As a first step, noise and noise related performance characteristics are under investigation, using statistical methods to analyze the light output. In the next year, work will concentrate on the evaluation of the spatial resolution. This will be done using Fourier transform techniques, based on the line spread function. Work will also include an evaluation of the geometric uniformity and granularity of the XII. In the next year, work will continue on the spatial resolution. Also evaluation of video systems coupled to x-ray image intensifiers will be initiated. This program hopefully will build upon that undertaken at the Bureau of Radiological Health covering x-ray tubes, screen and film, by seeking criteria for evaluation, test procedures, specifications and nomenclature which as far as possible will be common to all.